(a) Field of the Invention
The present invention relates to a medical instrument for manipulating internal organs of the body, having a retractor body arranged at the distal end of a rod, guided in a shaft which is provided with a handle at its proximal end and is guided to be axially displaceable in the shaft, to bring the retractor body into either a straight or an open position.
(b) Description of the Prior Art
Endoscopic operations in the abdominal cavity on the one hand assume that a body cavity is dilated by means of body cavity gas, and on the other hand that there is free access to the organ to be investigated or treated. If free access to a certain organ is not possible, that is, if the part or region of the organ or the entire organ to be investigated and to be treated is hidden by another organ, the obscured region of the organ concerned must be exposed.
The organ to be treated is exposed or manipulated according to the known art using forceps or, as described in German Patentschrift 3 709 706, by means of three spring resilient elements designed like fingers which have spherical elements at their distal ends, that is directly at the ends engaging the organ or the like to be manipulated, to avoid injury to the organ.
The previously known disadvantage of the manipulators is that they allow only inadequate manipulation because of the insufficient transfer of force and may also cause injury at least in some cases. The danger that the individual fingers will bend as a result of the engaging force exists in particular in the manipulator of German Patentschrift 3 709 706, due to the relatively low mechanical stability. The finger elements, which can be included in the outer shaft are subject to uncontrolled movement due to bending when being removed from the shaft, as a result of which the usability is considerably impaired. A further disadvantage of this manipulator resides in the fact that the retracting force of the retractor elements is derived from the spring bias of the same, and the retracting force is therefore fixed in each case at its maximum and cannot be influenced. This may result in insufficient retracting force, so that if the surgeon is unaware that the retractor is at an equilibrium of the retracting force and the retracting resistance, with the result that the retractor path will not be limited by the shaft of the instrument, but rather by the retracting resistance, so that the retracting force then strains the manipulated organ in an uncontrolled manner. This may lead to organ damage.
It is therefore an object of the present invention to address these disadvantages associated with known retractors, and enable, on the one hand relatively high forces to be exerted when the organ is manipulated, and on the other hand to avoid possible improper handling at the manipulator from leading to injury of the organ or the like.